Long Mott Energy, LLC – Long Mott Generating Station Xe-100 Power Reactor Application

On this page:

• Project Overview
• Key Milestones
• Historic and Cultural Resources Section
• Environmental Review Documents
• Contacts

Project Overview

The staff of the U.S. Nuclear Regulatory Commission (NRC) is currently engaged in review activities for the construction permit application from Long Mott Energy, LLC (LME), for the Xe-100 power reactor to be located in Calhoun County, Texas. The Xe-100 project is supported by the U.S. Department of Energy’s Advanced Reactor Demonstration program and would be used to demonstrate the X Energy Xe-100 reactor technology.

• Application Review Documents

Environmental Review Documents

Availability of the Historic and Cultural Resources Section of NRC's Environmental Assessment for the Issuance of a Construction Permit for the Long Mott Generating Station

The U.S. Nuclear Regulatory Commission (NRC) is conducting an environmental review of an application submitted by Long Mott Energy, LLC for a construction permit (CP) to build four Xe-100 reactor modules at the Long Mott Generating Station (LMGS) site in Calhoun County, Texas. The NRC staff’s review is conducted in accordance with 10 CFR Part 51, “Environmental Protection Regulations for Domestic Licensing and Related Regulatory Functions,” which implements the requirements of the National Environmental Policy Act of 1969, as amended (NEPA). The NRC staff is conducting a Section 106 review of the application in accordance with the National Historic Preservation Act of 1966, as amended (NHPA). Consistent with 36 CFR Part 800.8(c), “Use of the NEPA process for Section 106 purposes,” the NRC is using the NEPA process to comply with Section 106 of the NHPA in lieu of the procedures outlined in 36 CFR 800.3 through 800.6.

Section 106 implementing regulations at 36 CFR 800.2(d)(2) direct the Federal agencies to provide the public with information about its undertaking and its effects on historic properties, including seeking comments and input from the public. The following section satisfies that requirement.

The proposed undertaking is to issue a CP to build four Xe-100 reactor modules at the LMGS site in Calhoun County, Texas. The proposed project is intended to supply electrical power and steam to the adjacent Seadrift Operations (SDO) facility. Each Xe-100 reactor module would be capable of producing 80 megawatts-electric of electrical power or approximately 200 megawatts-thermal of steam. Construction of the facility would occur on approximately 1,537 acres adjacent to the SDO in Seadrift, Texas. The Area of Potential Effects (APE) for the project consists of the 1,537-acre site and encompasses all areas required for LMGS-related construction and operational activities. The APE also accounts for a 0.5 mile (0.58 kilometer) buffer surrounding the project site to account for potential impacts to offsite historic and cultural resources and historic properties.

The NRC is conducting an environmental review to evaluate potential impacts to historic properties, as required by Section 106 of the NHPA. NRC’s confirmatory review included the assessment of Long Mott Energy’s application (ML25090A063), their identification of historic and cultural resources, historic properties, and an evaluation of potential impacts resulting from the proposed undertaking. NRC staff also consulted with the Advisory Council on Historic Preservation, the Texas Historical Commission, and 21 Federally Recognized Tribes. 

Based on the staff’s review of Long Mott Energy’s environmental report portion of the application, the archaeological and architectural surveys conducted by their contractor, and the staff’s independent assessment, the NRC staff has made a preliminary determination that no historic properties would be affected by the undertaking, as defined in 36 CFR 800.4(d)(1). Additionally, there would be no significant impacts to historic and cultural resources under NEPA.

Long Mott Draft HCR Section - March 2026 (ML26050A453)

Pursuant to 36 CFR 800.8(c), the NRC staff is soliciting comments on the NRC’s Section 106 finding and the cultural resources information contained at the link above.  Comments on the draft historic and cultural resources section may be provided to Jennifer Davis, Senior Environmental Project Manager/Archaeologist, at Jennifer.Davis@nrc.gov or Joe O’Hara, Environmental Project Manager, at Joe.OHara@nrc.gov.  
 

Key Milestones

* The review team will begin interacting with the Advisory Committee on Reactor Safeguards (ACRS) as soon as portions of the safety evaluation are approved by NRC staff managers. The ACRS may write a letter to the staff commenting on the evaluation.
** The NRC staff has made a decision to first prepare an Environmental Assessment to document its review of the environmental impacts associated with the proposed Long Mott Generating Station. In accordance with the National Environmental Policy Act, at the conclusion of this process, a determination will be made regarding whether to prepare a Finding of No Significant Impact (FONSI) or an Environmental Impact Statement (EIS). If a FONSI cannot be reached the NRC will commence preparing an EIS and this schedule may be subject to change.

Contacts